The present invention relates to a power converter and more particularly, to a technique for increasing the productivity of the power converter.
A power converter, for example, an inverter includes, as its main constituent elements, a power module having a plurality of switching semiconductor elements, a control circuit board for controlling the operations of the plurality of switching semiconductor elements in the power module, and a smoothing capacitor connected to a DC side of the power module. Respective constituent elements including the aforementioned elements are accommodated within a single casing.
The inverter thus arranged is located between a DC power source and an electrical load so that a DC power source side of the inverter is connected to both ends of the smoothing capacitor and an electrical load side of the inverter is connected to an AC side of the power module. In the inverter, a signal indicative of a torque command or a rotation command is input to the control circuit board so that the ON/OFF operations of the plurality of switching semiconductor elements are controlled with use of a drive signal received from a drive circuit board via the control circuit board, whereby a power to be supplied to the electrical load from the DC power source is converted.
In the inverter, current paths from the DC power source to the smoothing capacitor and to the power module as well as current paths from the power module to the electrical load side are made, in many cases, in the form of bus bars made of plate-shaped conductors. For this reason, the power module has a plurality of electrodes or terminals for interconnection with the plate-shaped conductors (bus bars). The plurality of electrodes or terminals are made in the form of plate-shaped conductors and are exposed outside of the case of the power module.
One of background arts of the power converter thus arranged is known as disclosed, for example, in JP-A-2000-216331. Disclosed in JP-A-2000-216331 is such a technique that lamination conductors are stacked on the outer terminals of the power module and the outer terminals and the lamination conductors are connected by bolts.
When such a power converter as the aforementioned inverter is assembled, the power module is located with the casing and then the plurality of electrodes or terminals provided to the power module and the plate-shaped conductors (bus bars) are interconnected by tightening members such as bolts as in the background art. Upon the interconnecting works between the electrodes or terminals and the conductors, threaded holes provided in the both are positioned and then the both members are interconnected by the tightening members.
In such a power converter requiring a high miniaturization or compactness as an inverter used in a vehicle, the power module and the smoothing capacitor are located, in many cases, close to the wall of the casing. In such a case, it is hard to secure a sufficient working zone in the vicinity of the plurality of electrodes or terminals provided to the power module, it becomes highly difficult to confirm the positioning to the plate-shaped conductors (bus bars) and thus the interconnecting works between the plurality of electrodes or terminals provided to the power module and the plate-shaped conductors (bus bars). For this reason, it has so far been demanded to such a technique as to increase a working efficiency upon assembling the power converter including the interconnecting works between the plurality of electrodes or terminals provided to the power module and the plate-shaped conductors (bus bars) and eventually to increase the productivity of the power converter.